Summary
In the treatment of chronic hepatitis B virus (HBV) infection, polymerase inhibitors successfully suppress HBV DNA production. However, the production of viral proteins continues unhindered, ...which hampers viral clearance. Here, we screen for compounds that suppress HBV transcription, which would prevent viral protein production. A total of 640 FDA‐approved drugs were evaluated for their ability to inhibit HBV transcription in a transfection‐based HBV reporter assay. The assay was performed in the presence and absence of the HBV accessory protein X (HBx), which is essential for in vivo HBV RNA transcription. We observed that in the absence of HBx 47, and in the presence of HBx 24 compounds suppressed transcription by more than 20%. We selected the 24 most potent compounds in each condition for further analysis. On average, the selected compounds reduced transcription by 33.9% (range: 24.1–65.8%) in the absence of HBx expression, and 30.6% (range: 20.4–48.9%) in the presence of HBx. The two selections of 24 compounds had 12 compounds in common, resulting in a final selection of 36 compounds, which were evaluated for their capacity to suppress HBV replication in constitutively HBV‐replicating HepG2.2.15 cells. Twenty‐three of these compounds reduced HBV replication by interfering with RNA transcription. Further analysis revealed that one of the compounds, terbinafine, potently and specifically suppressed HBx‐mediated HBV RNA transcription in HepG2 cells. Inhibition of HBV protein production is a promising step towards HBV clearance. In combination with an HBV polymerase inhibitor, the added suppression of HBV RNA transcription may markedly improve antiviral treatment outcome.
For phylogenetic comparison of hepatitis B virus (HBV) isolates, often a region of the HBV surface gene is analysed. Because the surface gene completely overlaps the polymerase gene, its evolution is ...constrained, and it may not be the best choice for genetic comparison of HBV isolates. Analysing serial sample pairs of 33 chronically HBV‐infected, untreated patients, with a cumulative follow‐up of 184 years, the synonymous and nonsynonymous substitution rates of a part of the overlapping HBV surface and polymerase genes were compared to those of a nonoverlapping part of the HBV core gene. The substitution rate of the HBV core gene was higher (8.15 × 10−4vs 4.57 × 10−4 substitutions/site/year) than that of the surface gene. The difference was mainly due to a significantly lower synonymous substitution rate in the surface gene, with dN/dS ratios of 0.412 in the core gene and 0.986 in the surface gene. Contrary to the core gene, the number of substitutions in the surface gene was higher in low viraemic hosts, who control HBV infection by suppressing replication. The number of substitutions in the core gene correlated more strongly with the duration of follow‐up. The overlapping HBV surface and polymerase genes experience strong negative selection, which limits the number of substitutions. Because the HBV core gene reflects the duration of infection more accurately, it is more suitable for the analysis of short‐term viral evolution and of hepatitis B transmission chains.
•WG-am is a naturally occurring dipeptide from elite controllers with anti-HIV activity.•WG-am is a new antiviral compound with two independent mechanisms of action against HIV.•WG-am binds to gp120 ...CD4 binding pocket and blocks the binding between HIV-1 and the host cell.•WG-am also exerts a post-entry but pre-integration antiviral effect related to RT-activity.
Enhanced levels of a dipeptide, WG-am, have been reported among elite controllers – patients who spontaneously control their HIV-1 infection. This study aimed to evaluate anti-HIV-1 activity and mechanism of action of WG-am.
Drug sensitivity assays in TZM.bl cells, PBMCs and ACH-2 cells using WT and mutated HIV-1 strainswere performed to evaluate the antiviral mechanism of WG-am. Mass spectrometry-based proteomics and Real-time PCR analysis of reverse transcription steps were performed to unravel the second anti-HIV-1 mechanism of WG-am.
The data suggest that WG-am binds to the CD4 binding pocket of HIV-1 gp120 and blocks its binding to the host cell receptors. Additionally, the time course assay showed that WG-am also inhibited HIV-1 at 4–6 hours post-infection, suggesting a second antiviral mechanism. Drug sensitivity assays under acidic wash conditions confirmed the ability of WG-am to internalise into the host cell in an HIV independent manner. Proteomic studies showed a clustering of all samples treated with WG-am independent of the number of doses or presence or absence of HIV-1. Differentially expressed proteins due to the WG-am treatment indicated an effect on HIV-1 reverse transcription, which was confirmed by reverse transcriptase polymerase chain reaction (RT-PCR).
Naturally occurring in HIV-1 elite controllers, WG-am stands out as a new kind of antiviral compound with two independent inhibitory mechanisms of action on HIV-1 replication. WG-am halts HIV-1 entry to the host cell by binding to HIV-1 gp120, thereby blocking the binding of HIV-1 to the host cell. WG-am also exerts a post-entry but pre-integration antiviral effect related to RT-activity.
•ERα/ERβ ratios are defined in T47D-ERβ cells with tetracycline dependent ERβ.•ERα/ERβ ratios of T47D-ERβ cells can mimic ratios in breast, prostate and uterus.•Conditions at which the T47D-ERb cells ...best mimic in vivo tissues are established.•Estradiol induced cell proliferation varies with the ERα/ERβ ratio.•ERβ levels in MCF-7 and native T47D cell lines do not reflect levels in tissues.
T47D-ERβ breast cancer cells with tetracycline-dependent ERβ expression and constant ERα expression can be used to investigate effects of varying ERα/ERβ ratios on estrogen-induced cellular responses. This study defines conditions at which ERα/ERβ ratios in T47D-ERβ cells best mimic ERα/ERβ ratios in breast and other estrogen-sensitive tissues in vivo in rat as well as in human.
Protein and mRNA levels of ERα and ERβ were analyzed in T47D-ERβ cells exposed to a range of tetracycline concentrations and compared to ERα and ERβ levels found in breast, prostate, and uterus from rat and human origin.
The ERα/ERβ ratio in T47D-ERβ cells exposed to >150ng/ml tetracycline is comparable to the ratio found in rat mammary gland and in human breast tissue. The ERα/ERβ ratio of other estrogen-sensitive rat and human tissues can also be mimicked in T47D-ERβ cells. The ERα/ERβ ratio found in MCF-7 and native T47D breast cancer cell lines did not reflect ratios in analyzed rat and human tissues, which further supports the use of T47D-ERβ cells as model for estrogen-responsive tissues. Using 17β-estradiol and the T47D-ERβ cells under the conditions defined to mimic various tissues it could be demonstrated how these different tissues vary in their proliferative response.
Chronic infection with the hepatitis B virus (HBV) affects an estimated 257 million people worldwide and can lead to liver diseases such as cirrhosis and liver cancer. Viral replication is generally ...considered not to be cytopathic, and although some HBV proteins may have direct carcinogenic effects, the majority of HBV infection-related disease is related to chronic inflammation resulting from disrupted antiviral responses and aberrant innate immune reactions. Like all cells, healthy and HBV-infected cells communicate with each other, as well as with other cell types, such as innate and adaptive immune cells. They do so by both interacting directly and by secreting factors into their environment. Such factors may be small molecules, such as metabolites, single viral proteins or host proteins, but can also be more complex, such as virions, protein complexes, and extracellular vesicles. The latter are small, membrane-enclosed vesicles that are exchanged between cells, and have recently gained a lot of attention for their potential to mediate complex communication and their potential for therapeutic repurposing. Here, we review how HBV infection affects the communication between HBV-infected cells and cells in their environment. We discuss the impact of these interactions on viral persistence in chronic infection, as well as their relation to HBV infection-related pathology.
BackgroundThe global distribution of HIV-1 subtypes is evolving, which is reflected in the Swedish HIV cohort. The subtype HIV-1A6, which may be prone to developing resistance to cabotegravir, is the ...most common subtype in Ukraine.AimWe aimed to examine trends in HIV-1 subtype distribution in Sweden, with a special focus on HIV-1A6, and to describe the virology, demography and treatment of Ukrainian people living with HIV (PLWH) who migrated to Sweden in 2022.MethodsData about PLWH in Sweden are included in a national database (InfCareHIV). We used the online tool COMET to establish HIV-1 subtypes and the Stanford database to define drug resistance mutations. We investigated the relation between virological characteristics and demographic data.ResultsThe early epidemic was predominated by HIV-1 subtype B infections in people born in Sweden. After 1990, the majority of new PLWH in Sweden were PLWH migrating to Sweden, resulting in an increasingly diverse epidemic. In 2022, HIV-1A6 had become the sixth most common subtype in Sweden and 98 of the 431 new PLWH that were registered in Sweden came from Ukraine. We detected HIV RNA in plasma of 32 Ukrainian patients (34%), of whom 17 were previously undiagnosed, 10 had interrupted therapy and five were previously diagnosed but not treated. We found HIV-1A6 in 23 of 24 sequenced patients.ConclusionThe molecular HIV epidemiology in Sweden continues to diversify and PLWH unaware of their HIV status and predominance of HIV-1A6 should be considered when arranging care directed at PLWH from Ukraine.
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